Marieke van Son

145 PREDICTION MODELS FOR BF AFTER FOCAL SALVAGE HDR-BT Table 1 Continued Primary treatment n (%) or median (IQR) Missing (%) Initial NCCN risk group Low risk Intermediate risk High risk 27 (18.0) 56 (37.3) 59 (39.3) 5.3 ADT use (adjuvant/neoadjuvant) 30 (20.0) 0 ADT duration (months) (n=30) 36.0 (18.0-36.0) 10 PSA nadir post-primary treatment (ng/ml) 0.56 (0.25-1.10) 3.3 FS-HDR-BT n (%) or median (IQR) Missing (%) Pre-salvage PSADT (months) 15.7 (11.6-23.6) 0 Interval between primary and salvage treatment (months) 97 (63-128) 0 Age at FS-HDR-BT (years) 71.5 (±5.0) 0 Pre-salvage PSA (ng/ml) 4.88 (2.80-6.80) 0 Imaging T-stage at FS-HDR-BT T1-2a T2b-2c T3a-3b 45 (30.0) 40 (26.7) 65 (43.3) 0 Gleason at FS-HDR-BT 3+3=6 3+4=7 4+3=7 Sum score=8 Sum score=9/10 14 (9.3) 27 (18.0) 21 (14.0) 6 (4.0) 14 (9.3) 44.7 Tumour location Base Midgland Apex Combination base/midgland/apex Seminal vesicle Prostate body and seminal vesicle 21 (14.0) 29 (19.3) 21 (14.0) 31 (20.7) 23 (15.3) 25 (16.7) 0 Seminal vesicle involvement at FS-HDR-BT 48 (32.0) 0 GTV at FS-HDR-BT (cm 3 ) 3.0 (1.7-5.1) 0.7 D95% CTV (Gy) 18.8 (17.4-19.7) 0 V200% CTV (%) 26.3 (18.4-27.9) 0 Post-salvage PSA nadir (ng/ml) 0.76 (0.26-1.30) 0 Post-salvage time to PSA nadir (months) 6.1 (3.6-9.6) 0 Percentage PSA reduction 84.2 (68.3-92.9) 0 Biochemical recurrence 61 (40.7) 0 Follow-up time (months) 25.1 (13.5-36.1) 0 Abbreviations:IQR =interquartilerange.SD =standarddeviation.EBRT=externalbeamradiotherapy.LDR=low- doserate.HDR=high-doserate.PLND=pelviclymphnodedissection.NCCN=nationalcomprehensivecancer network. ADT=androgen deprivation therapy. PSA=prostate specific antigen. FS-HDR-BT=focal salvage high-dose-ratebrachytherapy.PSADT=PSAdoublingtime.GTV=grosstumourvolume.D95%=doseto95% of the volume. V200%=volume receiving200%ormoreof theprescribeddose. CTV=clinical target volume. 8